1. ¹Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
2. ²The Kresge Eye Institute/Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI, USA

Correspondence: Professor XY Wu, Department of Ophthalmology, Qilu Hospital of Shandong University, Wenhua Xi Road 107, Shandong Province, Jinan 250012, China. E-mail: xywu8868@163.com

Received 15 November 2007; Revised 27 November 2007; Accepted 27 November 2007; Published online 15 January 2008.

Abstract

Toll-like receptors (TLRs) are key components of the innate immune system that detect microbial infection and trigger antimicrobial host responses. To determine the role of TLR2 in the expression of pro- and anti-inflammatory cytokines in corneal fibroblasts challenged by fungi, we used siRNA specific for TLR2 to knockdown TLR2 expression in telomerase-immortalized human stroma fibroblasts (THSF). TLR2 expression was assessed by immunocytochemistry, reverse transcription (RT)-PCR and western blotting analyses, and we found that THSF transfected with TLR2-siRNA plasmid exhibited a reduced level of TLR2 when compared with the control cells transfected with empty plasmid. Then the transfected and control cells were stimulated by hyphae or conidia of Fusarium solu and mRNA levels of IL-1 and IL-10 were measured by real-time RT-PCR. We observed that stimulation of control cells with F. solu resulted in elevation of IL-1 and IL-10 mRNA with hyphae being more stimulatory than conidia. In contrast, F. solu-stimulated IL-10 production by transfected THSF was severely impaired (with a decrease of approximately 82% in hyphae and 70% in conidia stimulation), while IL-1 production was partially inhibited (with a reduction of 60 and 54% in hyphae and conidia stimulations). Our results suggested that TLR2 is a major pattern recognition receptor able to detect F. solu in vitro and may play the anti-inflammatory role through the induction of IL-10. This may lead to a better understanding of the pathogenesis of cornea fungal infections and immune evading.